JP2002122089A - Lubricating structure in fluid machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly lubricate a radial bearing, without trapping the oil in the engagement part of a gear mechanism. SOLUTION: An axis 191 of a rotary shaft 19 and an axis 201 of a rotary shaft 20 are mounted at the same height position. An engagement part K of a gear 34 and a gear 35 is located at a height same as the height position of the axes 191, 201. An upper limit of an oil level Y0 of the lubricating oil Y is lower than the engagement part K of the gear 34 and the gear 35. The lower limit of the oil level Y0 of the lubricating oil Y is higher than the height positions of a lowermost position S10 of a clearance S1 of a radial bearing 37, and a lowermost position S20 of a clearance S2 of a radial bearing 38.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for moving a fluid transfer body on each of the rotating shafts based on rotation of a plurality of rotating shafts arranged in a horizontal direction, and transferring the fluid by the operation of the fluid transfer body. A fluid machine in which a plurality of the rotating shafts are rotatably supported by respective radial bearings in an oil storage chamber, and the plurality of the rotating shafts are synchronously rotated using a gear mechanism, and the gear mechanism is accommodated in the oil storage chamber. In the lubrication structure.

[0002]

2. Description of the Related Art Roots pumps, which are a kind of vacuum pumps disclosed in Japanese Patent Application Laid-Open Nos. 2-157490 and 8-14172, rotate in a state where two adjacent rotors mesh with each other. Is done. Rotate while meshing 2
The rotation of the individual rotors transfers gas. One of the rotating shafts of the rotor obtains driving force from a motor, and the other rotating shaft obtains driving force from the one rotating shaft via a gear mechanism.

[0003] Lubricating oil is stored in a chamber accommodating the gear mechanism. The rotating shaft is rotatably supported by a radial bearing in a room accommodating the gear mechanism. The lubricating oil that lubricates the gear mechanism also lubricates the radial bearing.

[0004]

Assuming that the oil level of the stored oil is high enough to reach the meshing portion of the gear mechanism, the stored oil is trapped in the meshing portion between the meshed gears. Such oil confinement causes problems such as generation of abnormal noise and increase in oil temperature. In the apparatus disclosed in JP-A-8-14172, a virtual inclined line connecting the axes of a pair of rotating shafts is 40 °
The height positions of the two rotating shafts are different so as to be 50 ° so that the oil level does not reach the meshing portion between the pair of gears. However, if the height positions of the two rotating shafts are made different so that the inclination line becomes 40 ° to 50 °, it becomes difficult to satisfactorily lubricate the radial bearing corresponding to the rotating shaft located at a high position. Insufficient lubrication of the radial bearing reduces the durability of the radial bearing.

It is an object of the present invention to provide a lubricating structure capable of satisfactorily lubricating a radial bearing without causing oil confinement at a meshing portion of a gear mechanism.

[0006]

SUMMARY OF THE INVENTION In order to achieve this, the present invention moves a fluid transfer body on each of the rotation shafts based on rotation of a plurality of rotation shafts arranged in a horizontal direction, and operates the fluid transfer body by operating the fluid transfer body. In order to transfer the oil, the plurality of rotating shafts are rotatably supported by radial bearings in the oil storage chamber, and the plurality of rotating shafts are synchronously rotated using a gear mechanism, and the gear mechanism is moved to the oil storage chamber. In the invention of claim 1, the position of the meshing portion between the adjacent gears of the plurality of gears is set at the lowest position of the gap between the outer ring and the inner ring of the plurality of radial bearings. Above the position, the lower limit of the oil level in the oil storage chamber is equal to or greater than the position of the lowest part of each gap, and the upper limit of the oil level in the oil storage chamber between adjacent gears of the plurality of gears. Engaging position It was lower than.

[0007] Such a setting of the height of the oil surface enables sufficient lubrication of the radial bearing while avoiding trapping of oil in the meshing portion between the gears to be meshed. Claim 2
In the present invention, in claim 1, the plurality of rotation shafts are arranged at substantially the same height.

A configuration in which a plurality of rotating shafts are arranged at substantially the same height facilitates setting of the oil level. Claim 3
According to the invention, in the fluid machine according to any one of claims 1 and 2, the plurality of rotation shafts are arranged in parallel, and a rotor is arranged on each of the rotation shafts. The upper rotor is meshed with each other, and a plurality of pump chambers or a single pump chamber accommodating a plurality of meshed rotors as a set are provided, and the oil storage chamber is provided at an end of the pump chamber. Vacuum pump.

[0009] Lubricating oil can be used to remove heat generated by fluid compression. According to a fourth aspect of the present invention, in the third aspect, an oil level in the oil storage chamber is higher than a position of a lowermost portion of a peripheral surface of each of the rotating shafts.

[0010] Cooling of the rotating shaft is effective in removing heat generated due to fluid compression. If the rotating shaft is immersed in the stored oil, the cooling efficiency of the rotating shaft increases. According to a fifth aspect of the present invention, in any one of the third and fourth aspects, the fluid machine is a multi-stage vacuum pump in which a plurality of pump chambers are arranged in an axial direction of the rotating shaft, and the plurality of pumps are provided. The chamber volume is
It becomes smaller in the order approaching the oil storage chamber along the axial direction of the rotating shaft, and the fluid is transferred through the plurality of pump chambers in the order in which the volume becomes smaller.
The oil reservoir was adjacent to the minimum volume of the pump chamber.

The pump chamber with the smallest volume is the hottest spot. The configuration in which the oil storage chamber is adjacent to the pump chamber having the minimum volume is effective in improving the efficiency of removing heat generated due to fluid compression.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is embodied in a roots pump will be described below with reference to FIGS.

As shown in FIG. 2, the multi-stage roots pump 11
A front housing 13 is joined to a front end of the rotor housing 12 of the first embodiment, and a closing body 36 is joined to the front housing 13. A rear housing 14 is joined to the rear end of the rotor housing 12. The rotor housing 12 includes a cylinder block 15 and a plurality of partition walls 1.
6 As shown in FIG. 3B, the cylinder block 15 includes a pair of block pieces 17 and 18, and the partition 16 includes a pair of wall pieces 161 and 162. As shown in FIG. 2, the space between the front housing 13 and the partition 16, the space between the adjacent partition 16, and the space between the rear housing 14 and the partition 16 are each a pump chamber 3.
9, 40, 41, 42, 43.

A pair of rotating shafts 19 and 20 are rotatably supported by the front housing 13 and the rear housing 14 via radial bearings 21, 37, 22 and 38. The rotating shafts 19 and 20 are arranged horizontally and parallel to each other. The rotating shafts 19 and 20 are the partition 16
Has been passed through.

A plurality of rotors 23, 24, 25, 26, 27 as a fluid transfer body are integrally formed on the rotating shaft 19, and the same number of rotors 28, 29, 30, are formed on the rotating shaft 20.
31 and 32 are integrally formed. Rotors 23-32
Have the same shape and the same size when viewed in the direction of the axes 191 and 201 of the rotating shafts 19 and 20. Rotors 23, 24, 2
The thicknesses of the rotors 5, 26, 27 decrease in this order, and the thicknesses of the rotors 28, 29, 30, 31, 32 also decrease in this order.
The rotors 23 and 28 are housed in the pump chamber 39 in a state of being engaged with each other with a slight gap therebetween.
Reference numerals 9 are housed in the pump chamber 40 in a mutually engaged state. Similarly, the rotors 25 and 30 are connected to the pump chamber 41.
And the rotors 26 and 31 are in the pump chamber 42,
32 are accommodated in the pump chamber 43, respectively.

The gear housing 3 is mounted on the rear housing 14.
3 are assembled. The rotating shafts 19 and 20 penetrate through the rear housing 14 and protrude into the gear housing 33.
35 are fastened in a state where they are engaged with each other. An electric motor M is mounted on the gear housing 33. The driving force of the electric motor M is transmitted to the rotating shaft 1 via the shaft joint 10.
9, the rotating shaft 19 is rotated by the electric motor M in the direction of the arrow R1 in FIGS. 3 (a), 3 (b) and 3 (c). The rotating shaft 20 obtains a driving force from the electric motor M via the rotating shaft 19 and the gears 34 and 35, and the rotating shaft 20 is as shown by an arrow R2 in FIGS. 3 (a), (b) and (c). , And rotates in the direction opposite to the rotation shaft 19. That is, the rotating shafts 19 and 2
0 is synchronously rotated by a gear mechanism composed of gears 34 and 35 having the same number of teeth and the same diameter.

As shown in FIGS. 1A and 1B, the gear 3
Gear storage chamber 331 for housing a gear mechanism composed of 4, 35
The lubricating oil Y is stored therein, and is immersed below the gears 34 and 35. The lubricating oil Y is swept up by the rotation of the gears 34 and 35. Lubricating oil Y is supplied to gears 34 and 3
5. Lubricate the radial bearings 37,38. As shown in FIG. 2, a lip seal 44 is disposed on the rotation shaft 19 between the radial bearing 37 and the pump chamber 43. The lip seal 44 is provided in the gear storage chamber 3 serving as an oil storage chamber.
Leakage of the lubricating oil from 31 to the pump chamber 43 side along the peripheral surface of the rotating shaft 19 is prevented. A lip seal 45 is disposed on the rotating shaft 20 between the radial bearing 38 and the pump chamber 43. The lip seal 45 is provided in the gear housing chamber 33.
1 prevents leakage of the lubricating oil from the first to the pump chamber 43 side along the peripheral surface of the rotating shaft 20. Lubricating oil Y is lip seal 44,
Lubricate 45. As described above, the oil storage chamber is provided at the end of the pump chamber, and the bearing of the rotary shaft and the seal member are arranged therebetween so that they can be lubricated.

As shown in FIG. 1A, the axis 191 of the rotating shaft 19 and the axis 201 of the rotating shaft 20 are arranged at the same height. Therefore, the meshing portion K between the gear 34 and the gear 35 is at the same height position as the height positions of the axes 191 and 201. As shown in FIG. 1B, the lowest part S1o of the gap S1 between the inner ring 371 and the outer ring 372 of the radial bearing 37 and the lowest part S2o of the gap S2 between the inner ring 381 and the outer ring 382 of the radial bearing 38 are shown. At the same height. Meshing portion K between gear 34 and gear 35
Is above the lowest part S1o of the gap S1 and the lowest part S2o of the gap S2. The upper limit of the oil level Yo of the lubricating oil Y is lower than the meshing portion K between the gear 34 and the gear 35. The lower limit of the oil level Yo of the lubricating oil Y is equal to or higher than the height position of the lowest part S1o of the gap S1 and the lowest part S2o of the gap S2. In the illustrated example, the oil level Yo is the rotation axis 1
The lowermost parts 192 and 202 of the peripheral surfaces of the parts 9 and 20 are reached.

As shown in FIG. 2 and FIG.
A passage 163 is formed in 6. As shown in FIG. 3B, an inlet 164 and an outlet 165 of the passage 163 are formed in the partition 16. Adjacent pump chamber 39,4
0, 41, 42, 43 communicate with each other via a passage 163.

As shown in FIG. 3A, the block piece 18
Is formed so that an inlet 181 communicates with the pump chamber 39. As shown in FIG.
Is formed so that a discharge port 171 communicates with the pump chamber 43. The gas as a fluid introduced into the pump chamber 39 from the inlet 181 is transferred from the inlet 164 of the partition 16 via the passage 163 to the adjacent pump chamber 40 via the passage 163 by the rotation of the rotors 23 and 28. Hereinafter, similarly, the gas is transferred in the order of decreasing volume of the pump chamber, that is, in the order of the pump chambers 40, 41, 42, and 43. The gas transferred to the pump chamber 43 is discharged from the discharge port 171 to the outside. The rotors 23 to 32 are fluid transfer bodies that transfer fluid.

In the first embodiment, the following effects can be obtained. (1-1) If the oil level Yo of the lubricating oil Y is lower than the meshing portion K of the gears 34 and 35, the oil trapping phenomenon at the meshing portion K is avoided. Clearance S between radial bearings 37 and 38
If the oil level Yo of the lubricating oil Y is set at a height equal to or higher than the height position of the lowest part S1o, S2o of the lubricating oil Y, the lubricating oil Y is sufficiently supplied to the gaps S1, S2 of the radial bearings 37, 38. The lubrication of the radial bearings 37 and 38 is performed well.

(1-2) The axes 191 and 191 of the rotating shafts 19 and 20
In the configuration in which the height position of 201 is the same, the height difference between the lowest part S1o of the gap S1 and the meshing part K is the same as the height difference between the lowest part S2o of the gap S2 and the meshing part K. For example, assuming that the height position of the axis 191 of the rotating shaft 19 is higher than the height position of the axis 201 of the rotating shaft 20, the height difference between the lowest portion S1o of the gap S1 and the engagement portion K is smaller than the same height difference. Is also smaller. The lowest part S1 of the gaps S1 and S2
Regarding the ease of setting the oil level Yo above the height position of o and S2o and below the meshing portion K, the gaps S1 and S2
The height difference between the lowermost parts S1o, S2o and the meshing part K of the second two should be as large as possible. Rotating shaft 19, 2
The configuration in which the height positions of the 0 axis lines 191 and 201 are the same facilitates setting of the height position of the oil level Yo.

(1-3) Lubricating oil Y in gear housing chamber 331
Can be used to remove heat generated by gas compression.
The oil level Yo reaches the peripheral surfaces of the rotating shafts 19 and 20, and when the rotating shafts 19 and 20 are immersed in the stored oil, the rotating shafts 19 and 20 are rotated.
0 increases the cooling efficiency. The cooling of the rotating shafts 19 and 20 removes heat generated due to gas compression from the inside of the rotor housing 12 via the rotating shafts 19 and 20.
Such internal cooling is effective for removing heat generated due to gas compression.

(1-4) The pump chamber 43 having the smallest volume is the place where the temperature becomes the highest. The configuration in which the gear housing chamber 331 is adjacent to the pump chamber 43 having the minimum capacity is effective in improving the efficiency of removing heat generated due to gas compression.

It should be noted that the rotation shafts 19,
Although the 20 axes 191 and 201 have been described as having the same height, they may have substantially the same height as long as the above effects are obtained. In the present invention, the following embodiments are also possible. (1) Gaps S1, S2 between radial bearings 37, 38
The oil level Yo is set at the height position of the lowest part S1o, S2o. (2) The height position of the meshing portion K of the gears 34 and 35 is the gap S
The present invention is applied to a vacuum pump having a configuration in which the height positions of the rotating shafts 19 and 20 are different from the height positions of the lowermost parts S1o and S2o of S1 and S2 and are different from each other. (3) Transferring the fluid within a single pump chamber. (4) The present invention is applied to a vacuum pump having three or more rotating shafts. (5) The present invention is applied to a fluid machine other than the vacuum pump.

[0026]

As described above in detail, according to the present invention, the position of the meshing portion between the adjacent gears of the plurality of gears is set to be smaller than the position of the lowest part of the gap between the outer ring and the inner ring of the plurality of radial bearings. And the lower limit of the oil level in the oil storage chamber is equal to or greater than the position of the lowest part of each of the gaps, and the upper limit of the oil level in the oil storage chamber is the position of the meshing portion between adjacent gears among the plurality of gears. Therefore, there is an excellent effect that the radial bearing can be satisfactorily lubricated without causing oil confinement at the meshing portion of the gear mechanism in the fluid machine.

[Brief description of the drawings]

FIGS. 1A and 1B show a first embodiment, and FIG.
X-ray sectional view. (B) is a sectional view taken along line YY of FIG.

FIG. 2 is an overall plan sectional view of the multi-stage roots pump 11;

FIG. 3A is a sectional view taken along line AA of FIG. 2; (B) is FIG.
BB sectional drawing of FIG. (C) is a sectional view taken along line CC of FIG. 2.

[Explanation of symbols]

11 Multi-stage roots pump which is a vacuum pump. 19, 20
…Axis of rotation. 191, 201... Axis. 23, 24, 25,
26, 27, 28, 29, 30, 31, 32 ... rotors as fluid transfer bodies. Reference numeral 331 denotes a gear storage chamber serving as an oil storage chamber. 34, 35 ... gears constituting a gear mechanism. 37,38
… Radial bearings. 371, 381 ... inner ring. 37
2,382 ... outer ring. 39-43 ... Pump room. M: an electric motor that is a rotation driving means. Y: Lubricating oil. Yo ... oil level. S
1, S2 ... gap. S1o, S2o: lowest part. K: meshing part.

Claims (5)

[Claims] A plurality of rotating shafts for moving a fluid transfer member on each of the rotating shafts based on rotation of a plurality of rotating shafts arranged in a horizontal direction and transferring a fluid by the operation of the fluid transferring member. Each is rotatably supported by a radial bearing in an oil storage chamber, and a plurality of the rotating shafts are synchronously rotated using a gear mechanism, and the fluid machine accommodates the gear mechanism in the oil storage chamber, The position of the meshing portion between the adjacent gears of the gears is higher than the position of the lowest part of the gap between the outer ring and the inner ring of the plurality of radial bearings, and the lower limit of the oil level in the oil storage chamber is set to A lubricating structure for a fluid machine in which the upper limit of the oil level in the oil storage chamber is lower than the position of the meshing portion between adjacent gears of the plurality of gears, which is equal to or more than the position of the lowest part of the gap. 2. The lubricating structure according to claim 1, wherein the plurality of rotating shafts are arranged at substantially the same height. 3. The fluid machine according to claim 1, wherein the plurality of rotating shafts are arranged in parallel, and a rotor is arranged on each of the rotating shafts.
A plurality of pump chambers or a single pump chamber accommodating a plurality of rotors in a state in which the rotors on adjacent rotating shafts are engaged with each other, and the plurality of rotors engaged with each other are housed as a set. The lubrication structure for a fluid machine according to any one of claims 1 and 2, wherein the lubrication structure is a vacuum pump having a storage chamber. 4. The lubricating structure in a fluid machine according to claim 3, wherein an oil level in the oil storage chamber is higher than a position of a lowermost portion of a peripheral surface of each of the rotating shafts. 5. The fluid machine is a multi-stage vacuum pump in which a plurality of pump chambers are arranged in the axial direction of the rotating shaft, and the volume of the plurality of pump chambers is set along the axial direction of the rotating shaft. The fluid is transferred through the plurality of pump chambers in order of decreasing volume, and the oil reservoir is adjacent to the pump chamber having the minimum volume. A lubricating structure for a fluid machine according to any one of claims 3 and 4.